1. Field of the Invention
The present invention relates to a method for checking a switching center. Switching-oriented processes are carried out in the switching center during the execution of application programs.
2. Description of the Related Art
The signaling for a first subscriber exemplifies such a switching-oriented process. Switching-oriented processes generally relate to the control of the connection during the setup or cleardown of a connection between the first subscriber and a second subscriber. The execution of the application programs is controlled by an operating system, which serves as a link between the application programs and the other electronic components of the computer. The operating system controls different operating functions of the computer and assumes the operation of central tasks such as the administration of the memory and the driving of the device.
Generally, an application program, performs the signaling and the control of the connection. With the signaling data and call data processed by it. However, due to its size, application programs used for the signaling and the control of the connection, have been very complex. This results in a high costs associated with their preparation and maintenance. Moreover, as of now, a separate application program has been utilized for each transmission protocol that can occur at a subscriber line or inter-exchange signaling. This, further renders the preparation and maintenance of the application programs more difficult.
However, the application programs can be simply prepared and maintained if a signaling program is used for signaling and when a subscriber connection program is used for the control of the connection. The signaling program and subscriber connection program are different programs that are independently programmed and tested. Both programs mutually send each other messages with the aid of the operating system. Also, the switching center contains a signaling program for each speaking subscriber. The same instruction sequence can be accessed during the processing of the signaling programs. This is also referred to as incarnations of the signaling program. There can also be a plurality of incarnations with respect to the subscriber connection program.
Each signaling program accesses the pertinent data set. The signaling data set, among other things, contains a status data indicating the operating state of the accessing signaling program. A call data set for the access of the respective subscriber connection program also belongs to each subscriber connection program.
During the setup and cleardown of a connection between two subscribers, a signaling program works together with a partner subscriber connection program. For example, the signaling data set contains at least one reference data with respect to the partner call data set.
In an error-free operation, there are no allocation problems between the signaling data sets and the signaling programs, on the one hand, and the call data sets, on the other hand. Measures for checking the allocation are also not known. However, erroneous or invalid allocations can arise as a result of errors during the programming and during equipment failures of the switching center.
The present invention is based on the object of proposing a simple method for checking the switching center and particularly the allocation of the data sets to the programs. The invention is further based on the object of proposing a line unit and a switching center, as well as a pertinent computer program for implementing the checking method.
The objectives are achieved by storing in a memory unit of the switching center a signaling data set. This signaling data set is accessed by a signaling program that is used for signaling for a first subscriber. The signaling data set contains a status data that indicates the state of operation for the accessing signaling program. A connection data set is stored in the memory unit of the switching center. This connection data set, which is accessed by a connection program, is used for controlling the connection between a first subscriber and a second subscriber. The signaling data also contains a reference data for referring to the connection data set.
Based on the status data of the signaling data set, the present method detects the operating state of the accessing signaling program. The reference data of the signaling data set is then read. In case the reference data has an inadmissible value for the determined operating state, an error treatment is carried out. This measure guarantees that an erroneous allocation of signaling data set and signaling program is recognized on time. Accordingly, sequential error cases can be precluded. Furthermore, it becomes possible to release the storage space again, which is occupied by erroneous allocations in the switching center.
In another embodiment of the present invention, the cited steps are carried out during the processing of a checking program, which is not a part of the signaling or subscriber connection program. As such, the switching center is checked independent of the status of the signaling or the subscriber connection programs. The checking program is started, for example, at times at which the switching center is not loaded.
In another embodiment the call data set contains a status data indicating the status of the accessing subscriber connection program. The call data set contains a reference data referring to the signaling data set, which is accessed by the partner signaling program, so that the subscriber connection program can detect the partner signaling program with which it cooperates. However, the reference data can also refer to another call data set, which is accessed by another subscriber connection program with which cooperation ensues as well. The preceding steps for checking the allocation are also carried out regarding the data of the call data set. Thus, allocation errors between call data sets and subscriber connection programs can be found.
If the steps are carried out for each signaling data set and for each subscriber data set, a complete checking ensues. Preferably, the checking is cyclically performed, so that the check of the first data set is started again after all data sets have been checked. The check either ensues with interruptions or without interruptions of the cycle, whereby the processor can assume different tasks, such as switching tasks, during interruptions.
In an embodiment of the invention, a fixed value of the status data indicates a quiescent state in which the accessing program is not processed. If a data set is found in which the status data has the value for the quiescent state, only a fixed reference value indicating that a reference is not present, is admissible for the reference data. Such a reference value is the reference value zero, for example. In this context, this is also referred to as zero-pointer, since the reference value does not point to a valid data set. Allocation errors can be simply recognized in that the reference data exhibits a value deviating from the fixed reference value in the quiescent state. Given an operating state deviating from the quiescent state, an erroneous allocation, on the other hand, can be simply recognized, since the reference value does not point to the beginning of a data set, for example.
In another embodiment of the invention, an error message is entered into an error file during the error treatment. The operator can eliminate the error at a later point in time on the basis of the error message. If the errors are automatically eliminated, the operator can discover the causes for the error message on the basis of the error message.
In another embodiment, an admissible reference data is written into the storage unit in the location of the inadmissible reference data. A simple error treatment results.
Furthermore, the invention relates to a line unit and to a switching center, as well as to a computer program by means of which the inventive method is implemented. Therefore, the above cited technical effects are also valid for the line unit, the switching center and the computer program.